rear gelatin filter

[sama]

Anybody here have the experience to use gelatin filter on a Canon 17 40 L ? May be some never realize that there is a built-in slot on this lens.

What is the purpose of this design as people mentioned that gelatin filter will probably degrade IQ badly. others stated "As long as it isn't scratched, a proper optical-grade gelatin filter (like Kodak) will be optically superior to any front-mounted glass or plastic filter."

Please share your views, experience etc.

 

[Kernuak]

Anybody here have the experience to use gelatin filter on a Canon 17 40 L ? May be some never realize that there is a built-in slot on this lens.

What is the purpose of this design as people mentioned that gelatin filter will probably degrade IQ badly. others stated "As long as it isn't scratched, a proper optical-grade gelatin filter (like Kodak) will be optically superior to any front-mounted glass or plastic filter."

Please share your views, experience etc.

I think with the slimline filters that are now available, there is less need to use one, unless wider or due to a bulging front element. I certainly didn't feel the need to use one when I had my 17-40.